Re: [Patch v5 08/19] perf/x86: Enable XMM sampling using sample_simd_vec_reg_* fields

["Mi, Dapeng" <dapeng1.mi@linux.intel.com>]

On 12/5/2025 7:25 PM, Peter Zijlstra wrote:
> On Wed, Dec 03, 2025 at 02:54:49PM +0800, Dapeng Mi wrote:
>
>> diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h
>> index 7c9d2bb3833b..c3862e5fdd6d 100644
>> --- a/arch/x86/include/uapi/asm/perf_regs.h
>> +++ b/arch/x86/include/uapi/asm/perf_regs.h
>> @@ -55,4 +55,21 @@ enum perf_event_x86_regs {
>>  
>>  #define PERF_REG_EXTENDED_MASK	(~((1ULL << PERF_REG_X86_XMM0) - 1))
>>  
>> +enum {
>> +	PERF_REG_X86_XMM,
>> +	PERF_REG_X86_MAX_SIMD_REGS,
>> +};
>> +
>> +enum {
>> +	PERF_X86_SIMD_XMM_REGS      = 16,
>> +	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_XMM_REGS,
>> +};
>> +
>> +#define PERF_X86_SIMD_VEC_MASK		GENMASK_ULL(PERF_X86_SIMD_VEC_REGS_MAX - 1, 0)
>> +
>> +enum {
>> +	PERF_X86_XMM_QWORDS      = 2,
>> +	PERF_X86_SIMD_QWORDS_MAX = PERF_X86_XMM_QWORDS,
>> +};
>> +
>>  #endif /* _ASM_X86_PERF_REGS_H */
> I don't understand this bit -- the next few patches add to it for YMM
> and ZMM, but what's the point? I don't see why this is needed at all,
> let alone why it needs to be UABI.

Currently these bits are only used in user space perf tools. Let me remove
it from the header perf_regs.h.


>